[SoltanWorld]

I think you have not place the {param} in link tag, it should be like this in BB code

<script type="text/javascript" src="forum/swplayers/silverlight/silverlight.js"></script>
<script type="text/javascript"  src="forum/swplayers/silverlight/wmvplayer.js"></script>

<div id='mediaspace'></div>

<script type='text/javascript'>
 var cnt = document.getElementById('mediaspace');
 var src = 'forum/swplayers/silverlight/wmvplayer.xaml';
 var cfg = {height:'250', width:'470', file:"{param}"};
 var ply = new jeroenwijering.Player(cnt,src,cfg);
</script>